Dilated amyloid cardiomyopathy in fibrinogen A α-chain amyloidosis R554L variant. (A) Endomyocardial biopsy (×100 magnification) in a 55-year-old patient with the AFib R554L variant and stage II CKD, whose echocardiography during evaluation for combined LKT showed dilated cardiomyopathy with ejection fraction of only 25% (patient 18, tables). Endomyocardial histology shows bright apple green birefringence of diffuse Congo red–positive endocardial and interstitial amyloid deposits. No additional pathology or potential causes for dilated cardiomyopathy other than amyloidosis were identified. (B) Strongly positive fibrinogen immunohistochemistry using rabbit anti–human fibrinogen 1:200 (Dako Cytomation Inc), in the same section of panel A. (C) Apical 4-chamber 2-dimensional echocardiographic view at end diastole, demonstrating a dilated and globular left ventricular cavity. (D) Imaging from M-mode echocardiogram in the same patient, demonstrating increased left ventricular dimensions and reduced function. (E) Parasternal long axis echocardiographic images of increased left ventricular end diastolic dimensions. (F) Invasive angiogram of the left coronary artery (right anterior oblique projection), showing a 40% stenosis in the proximal anterior descending artery (black arrow), lumen irregularity, and more minor narrowing in the intermediate vessel (dotted white arrow) and narrowing in the first septal perforator (white arrow). The patient's right coronary had minor irregularity (not shown).